FIG. 1 Shows a dynamic ice making apparatus which mainly comprises at least a plate-type or tubular evaporator 1. Cold refrigerant enters via a tube 11 into the evaporator 1 and exchanges heat with the chilled water or ice on the outer surface of the evaporator 1. After heat exchange, the refrigerant is vaporized into gas refrigerant due to absorption of heat. The gas refrigerant is then sucked in by a compressor contained in a refrigeration unit 12. After compression, cooling and expansion, the gas refrigerant becomes a cold refrigerant again and is recycled to the evaporator 1 for cooling purposes, forming a refrigerant recycling system.
As shown in FIG. 1, a chilled water feed tube 13 located above the evaporator 1 distributes chilled water downwardly to flow over the outer surface of the evaporator 1. As the chilled water flows downwardly thereover, its heat is absorbed by the cold refrigerant inside the evaporator 1 and a layer of ice is thus formed on the outer surface of the evaporator 1. When the ice has built up to a certain thickness (generally between 6 and 10 mm), it has to be removed into a container. The conventional defrosting method is to conduct high-pressure hot gas refrigerant discharged from an outlet of the compressor into the evaporator 1 via a hot gas tube 14 so that the thin layer of ice in direct contact with the hot surface of the evaporator 1 is melted and pieces of ice fall into a storage tank 15 below. Compared with other types of ice storage systems, the evaporation temperature of the refrigerant in the ice storage system of the dynamic ice making apparatus may be increased to -6 degrees Celsius, hence the capacity and energy efficiency of its compressor must be excellent. Besides, since the ice is stored separately from the evaporator 1, the dynamic ice making apparatus may be used not only in air-conditioning systems hut also in food refrigeration and industrial processes to reduce power load during peak hours. The dynamic ice making apparatuses are usually available in packages and their size is determined by manufacturers, not end users. In order to use an available dynamic ice making apparatus, the end user must prepare an ice storage tank of a considerable depth to accommodate the size of the apparatus. The deeper (generally more than 6 m) the tank, the better the performance, but such deep tanks are not very suitable for installation in existing buildings. In view of this drawback, dynamic ice making apparatuses have limited applications. Elimination of this drawback and improvement in conventional ice making apparatuses are therefore necessary.
In the conventional ice making apparatus, the ice storage tank 15 is located below the ice making apparatus, and the ice falls directly into the storage tank 15. Because of this arrangement, the ice is unevenly distributed and accumulates into a heap such as that shown in FIG. 1, hence reducing the effective capacity of the storage tank 15. Additionally, every ice making apparatus has only a single ice storage tank, which is very uneconomical in terms of effectiveness.
Some types of conventional apparatuses have improved storage tanks such as that shown in FIG. 2, wherein a screw propeller means mounted at an upper end of the storage tank 15 distributes the falling ice to the corners of the storage tank 15 so as to prevent the ice from piling into a heap. But such a design is only suited for storage systems with a single storage tank. There are also restrictions on the height and shape of the storage tank.
In the conventional ice storage system having a single storage tank, the ice storage tank 15 occupies a huge area, which is a burden because land is limited and very expensive in large cities. Moreover, it is not possible to have the storage tank and the main body of the ice making apparatus separately installed using the known art, and users are discouraged from procuring such apparatuses. It is therefore necessary to solve the problems of utilizing existing building structures (e.g., raft foundations) in the installation of ice making apparatuses and improving the arrangement of the main body of the apparatus and the ice storage tank so as to attract users.